This invention relates to a fluid feeding device which feeds fluids selectively into a body cavity through an endoscope.
Generally an endoscope contains a water feeding tube. Through the water feeding tube, water is fed to the distal end of the endoscope to wash the body cavity, the observation window and illumination window of the endoscope, thereby preparing for the examination of the body cavity. Every time the endoscope is used, water must be removed or drained from the tube. Particularly in an endoscope with a film loaded in the distal end portion, water, if remaining in the water feeding tube, may flow into a camera when the distal end cap is removed, thus inevitably wetting the objective lens and other parts of the camera. In the endoscope of this type it is therefore absolutely necessary to drain or remove water from the water feeding tube before the distal end cap is taken off.
To drain water from a water feeding tube, the following steps are required in a prior art fluid feeding device. First, a connection tube between the water feeding tube and a water reservoir is disconnected from the water feeding tube. Then, its free end is covered with the cushion of a finger. And at the same time air is pumped into the water feeding tube until the inner wall of the water feeding tube is dried. These steps are not only time-consuming but also possibly cause the water to flow from one or both ends of the water feeding tube. Thus, the water may wet the distal end portion and/or the proximal end portion of the endoscope.
The prior art fluid feeding device is defective in that, when two fluids besides air, such as washing water, defoaming agent, tissue-coloring agent and compressed carbon dioxide gas, are selectively fed into a body cavity, or when a pressurized washing water is to be fed from feeding means other than the water reservoir, new communication means should be used in place of the connection tube. Selective use of two communication means is complicated, and the operator may erroneously feed a wrong fluid into the body cavity. Further, use of two communication means hinders miniaturization of the fluid feeding device. The device is inevitably larger in size particularly when two liquids are used and two reservoirs are required.